As the third season of HBO’s Game of Thrones begins on Sunday, we’re more hard-pressed than ever to identify absolute good guys and absolute bad guys. That’s just one reason why the series is so great.

The demarcation between the second and third seasons is somewhat artificial: Game of Thrones is an ongoing epic of many stories, all of which are evolving, as are many of the characters. What is it beyond the show’s powerful performances, visuals, special effects, sex and blood-churning battle scenes that sets Thrones apart?

First, it’s about the characters and their relationship with power. Seemingly good characters can go bad because of power. At the same time, people we perceive as villainous can demonstrate surprising but still credible compassion at times.

Many of the female characters are as powerful as the men who would be kings. Some women, such as Brienne of Tarth (Gwendoline Christie) and young Arya Stark (Maisie Williams), display that power in traditional male ways: Brienne can wield a sword as well as any man, while Arya impersonated a boy in order to survive after her father’s execution. Others, such as Cersei Lannister (Lena Headey) and Daenerys Targaryen (Emilia Clarke) frequently out-think the men around them.

Life and loss in the Seven Kingdoms toughened Catelyn Stark (Michelle Fairley) into a formidable adversary to any man who threatens her family or her husband’s legacy.

Second, the men are often victims of their own masculine hubris. The series continues to focus on men in danger of becoming intoxicated by their own power, including Petyr “Littlefinger” Bailish (Aidan Gillen), the arrogant boy-king Joffrey Baratheon (Jack Gleeson), the scheming Tyrion Lannister (Peter Dinklage), Stannis Baratheon (Stephan Dillane) and the “kingslayer,” Jaime Lannister (Nikolaj Coster-Waldau). Even Robb Stark (Richard Madden) shows a moment of weakness with regard to his relationship with his mother in the new season.

Viewers unfamiliar with the books by George R.R. Martin were shocked by the execution of Ned Stark (Sean Bean), largely because they were given to expect that Stark would be the central storyline. But by the second season, the audience came to understand how much larger Martin’s vision is.

The series focuses on the “game” of the eternal power-play among the mythical Seven Kingdoms to determine who will occupy the Iron Throne. It is a multisided chess match, more than a little suggestive of geopolitics in any age in human history.

With seven kingdoms of action and characters to mine, HBO has limitless opportunity to introduce new cast members. Among this season’s newcomers are Ciern Hinds as Mance Rayder and Diana Rigg as Lady Olenna Tyrell. Rigg will have a chance to demonstrate the full range of her experience, and it’s magical.